The FT-Raman spectra of encrustations of Dirina massiliensis f. sorediata on a variety of substrata collected from several locations have been recorded and analysed. This is the first time that such a comprehensive spectroscopic study has been made of lichen encrustations of the same species on different substrata. This lichen is able to bring about deterioration in all six different lichen substrata studied. Calcium oxalate dihydrate is produced in significant amounts by the reaction of lichen-generated oxalic acid with various calcareous rock substrata, as well as particles of the particular substratum itself. However, for specimens growing on a non-calcareous substratum in an exposed maritime location only traces of calcium oxalate are produced and more noticeable quartz particles are incorporated into the thalli. The results indicate that this lichen can degrade its substratum highly effectively and there is evidence of different strategies being exhibited by lichens in different habitats and geographical locations.